Former vice president Cheney released from hospital after fifth heart attack
Thursday, February 25, 2010
Richard B. Cheney's fifth heart attack may add to the lore surrounding the seemingly indomitable former vice president. But his ability to survive repeated coronaries is more a testament to modern medicine's advances in detecting and treating the leading killer than any supernatural powers.
Many people think of heart attacks as inevitably dramatic events involving chest-grabbing emergencies. But many attacks identified today, although potentially serious, can cause little if any damage to the heart -- and may go unnoticed.
"It may seem incredible for someone to go through that five times," said Clyde Yancy, a cardiologist at Baylor University Medical Center in Dallas and president of the American Heart Association. "But it's not how many heart attacks as much as what kind of heart attack that matters."
Cheney, 69, who was released from the hospital Wednesday two days after suffering chest pain and a "mild" heart attack, has benefited from a steady improvement in the ability to diagnose heart disease and treat it, which has sharply reduced the death toll and improved the longevity and quality of life for survivors.
"It shows you the striking advances we have made," Yancy said. "But it also shows you that despite the best care, there are some patients who continue to have problems. We haven't cured heart disease."
A heart attack, or myocardial infarction, occurs when blood flow to the heart is restricted or cut off entirely, often when the arteries supplying the heart, which have been narrowed, are blocked by clots. More than 610,000 Americans have their first heart attacks each year, 325,000 have recurrent heart attacks and more than 141,000 die from the attacks, according to the American Heart Association.
Among the many advances in treating heart disease in recent years has been the development of sensitive new tests, called troponin assays, that identify heart attacks by measuring proteins released by heart muscle when it is damaged. Such tests can identify attacks that in earlier eras would never have been diagnosed.
"In the past, these are things we might not have even called a heart attack," said Douglas Weaver, head of cardiology at the Henry Ford Heath System in Detroit and past president of the American College of Cardiology. "It may technically be what we call a heart attack, but it's not the life-threatening ones that we think of."
In recent decades, the death rate from heart attacks has also fallen by more than a third -- one of the biggest successes in modern medicine. The drop in the deaths has been attributed to a combination of factors, including lifestyle improvements such as fewer Americans smoking cigarettes. But a large part of the success has resulted from better ways to prevent heart disease, such as identifying people with artery-clogging high cholesterol or artery-damaging high blood pressure and treating the conditions with drugs such as statins.
For those who suffer chest pain or other symptoms that can signal an impending heart attack, the attacks can be prevented by surgery, such as bypassing the blocked or narrowed arteries or reopening them with procedures known as angioplasties. These involve snaking a tiny balloon into the artery and inflating it to open the passageway, then leaving a tiny metal lattice sleeve -- or stent -- behind to prop it open. Angioplasties are also used when someone is having or just had a heart attack to minimize the damage.
Every time someone has a heart attack, even a minor one, it kills heart tissue, leaving scars that weaken the heart's pumping capacity.
Given that Cheney suffered his first heart attack at 37 in 1978, he was probably born with a propensity for heart disease. He underwent quadruple bypass surgery after his third attack in 1988 and subsequently received several angioplasties, which are commonly needed repeatedly when the arteries narrow again.
But Cheney's multiple heart attacks have clearly weakened his heart, which puts him at risk for potentially life-threatening complications, including irregular heart rhythms. In 2001, doctors gave him a sophisticated device called an implantable cardioverter defibrillator, which monitors the heart and delivers an electrical shock if it detects a life-threatening abnormal heart beat.
Drugs such as beta blockers and ace inhibitors can also help make a weakened heart function more efficiently, sometimes helping to restore heart capacity. Anti-clotting medication such as aspirin and Plavix can reduce the risk that clots will form and block narrowed arteries.
But Cheney's latest attack may indicate that his bypassed arteries have narrowed again, perhaps meaning he may need additional surgery or angioplasty.
"The amount of damage to the heart is one factor, but another one is the status of the arteries," said Christopher Cannon, a cardiologist at the Brigham and Women's Hospital in Boston. "This may be a sign the heart arteries may be a bit fragile."
Cheney faces about a 25 percent risk of having another major event, including another heart attack, in the next six months, Cannon said. Every additional heart attack increases his risk for heart failure, which can cause death or require a transplant.
"He's definitely chipping away at his heart," Cannon said.